Receptacle filling and liquid level control system



May 19, 1953 H. R. KARLEN 2,639,078

RECEPTACLE FILLING AND LIQUID LEVEL CONTROL SYSTEM Filed Sept. 28, 1949IN V EN TOR.

Harzy R fzar/an Patented May 19, 1953 UNITED STATE-s ATENT RECEPTACBEmrjflzz lin BIQU'IULEVEB Harvey R. Karlem. (lhicago lil assimon tailorCorporatiom. Chicago, 111., a corporation of Delaware.

Apflication September 28, 1949; Serialmo; 1183341 Cl. .226.1 27J 9Claims 1.

This-inventionrelates to automatic'accntrol sysE- temsand apparatus,andzpartlcularl'y liquidlevel controls; and: it. has to; do. moreespecially; with electrical asdistinguished from. mechanical meansforautomatically shutting-oil; astreammf liquid whena-receptaclezinto[which thezstream-is flowing isfilledtoapredetermined'ilevelz The'invention as herein illustrated is, an adjunctof automatic: coffee brewing equipment and Will bedealt with as-zsuchinthe ensuing detailed. description; but: there are many other uses 1 towhich it maytprofitably'he put; as: Will berevident to those who areversed in:the artof automatic liquid level? controls.

In. automatic coileetbrewers of the-type wherein hot; water is suppliedto-andperco'lates through a mass or. ground? coffee contained. Within a.re:- fill'able cartridge: andlthence ,fiowssby gravity 'into a decanteror other; receptaclelitha's been acommon practicetointili-ze-aweightqesponsivemecm anism in thenature of: a; beamscaleon-which the decanter is supported and-which functionsautomatically to: interrupt the -flowof hot water when the decanter? isfilled: with coffee brew to. a predetermined: level: anterare capableof: completely; satisfactory operation; but theinaccuracy is dependentin. con.- siderable measure upon their; being kept reason.-

ablycleanpand inproper; adjustment:- Inmany instances the brewersareownedandoperatedby -peOIQ1eiW'h@'. expect them to functionindefinitely mechanical devicess'can meet such unreasonableex-lcectations, and this is-true of such beam-scale mechanisms.- The:result is". that. no. adequate serviei-ng is regularly given,-. andultimately. some thingpbreaks down;

As applied to coffee brewers, the.v primary ob iect. of; this. inventionis, to provide. dependable meansv for automatically shutting. ofi.thetfl'ow. of hotwater and liquid. coffee brew. Whemthe. re.-ceiving-decanter isfilled .to anredetermined, level, and .whichis.unlikely tobecome. adverselyafiected by Wear or accumulated foreigndeposits.

A. further'object is to. provide means of: this character, which. doesnotentail. needv of. special attention on the part. ofthe personoperating the brewer, and which does. not. inanyv Way. impede.placement. and removal of thedecanter.

Still. anotherobject is to provicle apparatus: for carrying. out thesevarious'objects; and which: can easily bemaintainedinla strictlysanitary condition;

More. broadly it. is; an. object-i. or. the invention Mechanisms-of thatchan- 21 tcmrovideanonemechanicaltsys em-a nti tut, as well: as: annoys}rmethod; ,fom, antomatically shutting ofi= aystream-iofz liquid flowinginto a 1 re:- centaclerwhemwenv theliquid level in thereceptez- CIeI'jSGS tO a certain predetennined hei-ght preevided. onlythalti the;liquid be slightlt con iv electrically,

Inits applicatiomtoaeofiee brewers, theinvention-icontemnlatee-atnormally closed,=,elec.trically,- operated.water; shut-off: valve incombination with a manually "operablerstantingswitch and an electronic relay operative, when energized. to close:theaholdingqswitchlsaickrelay having ,aicontroll circuit. whichmcl-udesxthemoollof .cofieevbrew inthe; receiving: decanter. and: also,preferably, the. stream of; notice; brew; flowing into; the. decantertogether. with: an; electrode; which makes contactwith the: coffee; brewin the decanter when. the: deoanten is; filleah to; a predeterminedlevel and thus; closes-the; control, circuit. which -;is efiectivethrough the relay to: 91056.. the water shuteoflsval-ver Whemthe melay;control circuit is closed: through; the; pool. on c0flee-.-b:ew;.anegative cuteoff potential; is resultantly; applied. to the controligridvoithe relay, thus; interrupting the: nlatecurrent;and:czonseqnently de+energizing the :holding switch: windingand. eausing the con taets; thereof: to open. and the-rwatezz-shut-ofilvalve to: close: 1

Because aqueous; coileeebrew: is- 1 an exceedingly neon. electrical:conduotor;.. and-5 furthen becausez itisenotpermissible-15mm;thestandpoint of. safety or in accord withUnderwriters requirementssto emnloy, more; than; a. voits-,. I have; notbeen able. toe find. on devise. an electroemechanicalrelay?oapableoflreliableeoperationion the-infinitesireally; smallcurrent available: for operation.- of thepnesent; control: system asapplieclgto-coffee brewers: and: for: that; reason I have found; itnecessaryitmmake usezof a: highly sensitive electronic: relay which isresponsive towvoltage alone anriinotrdependent :upon current-flow imthecnntrol circuit 1 thereof-2. However; when: thei-nvention: isappliedztowcontrolol" the -.flow or; liquids of higher conductivity;orrwhenrconditions are such that? highcn voltages are permissible, itwill be possible to substitute for the electronic relay a simple;inexpensive electrmmecl'ianical' relay, or evens dispense with the:useof a relay entirely;

Referring newto" the. drawing which accom panics-z thisa specification Eum 1i issalschematic diagramzillustratlngv-an an plication:v Off. theinvention to. automatic cofiee bmwen;

Fig. 2 shows, in elevation, thcatop: portion ofia decanter to which isattached a metal collar and a conductive probe;

Fig. 3 is a transverse section taken at line 33 of Fig. 2; and

Fig. 4 is a view similar to Fig. 2 illustrating a modification whereinthe probe is a metallic stripe adhered to the surface of the decanter.

Referring first to Fig. 1, there is illustrated in vertical section amore or less diagrammatic representation of an automatic cofiee brewingapparatus A having a water heater B which ordinarily is installed withinthe housing of the apparatus, but is otherwise shown in furtherance ofclarity. An electronic relay C is also included in this figure of thedrawing.

The brewer A includes a sheet metal housing l within which is usuallyinstalled the water heater B together with a solenoid-operated valve |2which controls the flow of water to the heater. Mounted on the housingIn is a head l3 which carries a holder I4. A replaceable cofi'eecartridge |5 which is detachably connected to the holder M to dependtherefrom is provided with a discharge spout l6. A conduit |1 extendsfrom the water heater B to the holder I4 and serves to conduct hot waterwhich, when the valve I2 is open, passes from the heater into thecartridge and upwardly through the mass of ground coffee therein forescape by gravity out of the spout l6 into a decanter l8 which rests onan electrically-heated hot plate l9 mounted on the housing [0.

The valve I2 is normally closed, but opens upon energization of itswinding and remains open only so long as this winding continuesenergized. Water in the heater B is continuously maintained at amoderate temperature by a heater element (not shown), and a secondheater element 22 of relatively high wattage serves to quickly increasethe temperature in response to closure of a solenoid-operated switch 23.

Alternating current is supplied through a pair of line conductors 24 and25. When the manually operable starting switch 26 is closed, parallelcircuits are then completed through the winding 20 of the valve l2 andthrough the winding 21 of the switch 23. Thus, the valve |2 is openedand the heater 22 is energized whenever the switch 26 is closed so thatcofiee brew will almost immediately start flowing from the spout 6 intothe decanter l8, provided there is a servlceable charge of ground cofieethen in the cartridge l5.

It is possible for the operator to hold the switch 26 closed until thedecanter I8 is sufliciently filled, thus dispensing with the automaticliquidlevel control about to be described; but doing so would entail agood deal of lost time and so is not done except in rare instances whenthe auto matic control may temporarily be out of order.

Momentary closure of the manual starting switch 26 establishes aconnection between the line conductors 24, and the two primary windings30 and 3| of a power transformer 35, and as a result voltage is inducedacross the three seriesconnected secondary windings 32, 33 and 34. Itwill be observed that the secondary winding 32, together with thesecondary winding 33, supplies space current to a diode rectifier 36 andthat the secondary winding 34 supplies space current to a triode 31while the winding 33 supplies a filament heating current to both tubes.Both the diode 36 and the triode 31 are normally de-energized and bothbecome energized upon closure of the starting switch 26.

Included in the plate circuit of the triode 31 is the winding 38 of anelectromagnetic switch 40. This winding is energized in response toclosure of the transformer primary circuit and thereupon closes thecontacts of the switch 40 which are in shunt to the contacts of thestarting switch 25. The control grid 4| of the triode 31 is normally atcathode potential, thus permitting the space current to flow until anegative cut-off potential is subsequently impressed thereon in themanner hereinafter described. The valve 2 is accordingly held open andthe switch 23 held closed as long as the contacts of the switch 40remain closed, and this condition will continue until the space currentthrough triode 31 is cut off.

The space current path of the diode 36 includes two resistors 43 and 44in series. It will be obvious that the D. C. potential at terminal 45,resulting from the flow of space current through the diode and throughsaid resistors, is more negative than the D. C. cathode potential of thetriode 31. Assuming appropriately selected parameters, the potential atthe terminal 45 has a negative value, with respect to the cathodepotential, such that if applied to the control grid 4| 0! the triode 31the flow of space current through the triode will be cut off, thuscausing de-energization of the winding 38 and consequent opening of thecontacts of the switch 40 which immediately results in closure of thevalve 2 and opening of the contacts of the switch 23.

The control grid 4| is connected through a resistor 46 and conductor 41to the metal housing ID of the coffee brewer apparatus A, and theterminal 45 is connected through a conductor 48 to a terminal or bindingpost 50 which is supported by the housing I!) but electrically insulatedtherefrom. Connected at its lower end to the binding post 50 andsupported thereby is an upwardly projecting resilient metal arm 5|which, when the decanter is positioned on the hot plate [9, makescontact with a sheet metal collar 52 embracing the neck of the decanterand serving both as an electrical conductor and as a medium forattaching the lifting handle 53 to the decanter. A wire probe 54 iselectrically connected at one end to the collar 52 and extends, as bestshown in Fig. 2, over the top rim of the decanter and thence downwardlyinside the decanter where it terminates at a level to which the decanteris to be filled with coffee brew. When the decanter is thus filled, acircuit is established from the negative terminal 45 through theconductor 48, binding post 50, am 5 I, collar 52, probe 54, the pool ofcofiee brew in the decanter, the stream of coffee brew flowing from thespout I6 into the decanter, the conduit H, the housing l8 which iselectrically connected to said conduit, and the conductor 41 andresistor 46 to the control grid 4|. Thus the potential of the grid 4| isinstantly lowered to cut-ofi' with the result that the valve I2 isinstantly closed, and at the same time the energizing circuit of theheater element 22 is opened.

The capacitors 39 and 55 are filter elements serving to unify the directcurrent flow through the winding 38 and the resistor 44, respectively.The resistor 56 is a grid leak serving normally to maintain the controlgrid 4| at cathode potential; and the capacitor 51 functions conjointlywith the resistor 56 to form a time-delay loop the purpose of which isto maintain the control grid 4| at cut-off potential for a measurableperiod of time once the probe 54 has contacted the answers pooh f."coffee: brew: in the: decanter: Without this provision the; controlgrid: could? go: alternately" between cuts-off; andv non-cut-oiffpotentials,,thus repeatedly opening.- and closing the switch-1 icinrapid succession and in: turn the switch 23-; and valve: l2: until, thelevel, of; the coffee brew finally reached apoint atv which it couldmaintain continuous contact with the. end of; probe 5. To. prevent, suchfluttering; ofv the switch 40 and resultant fluttering of; thevalve i 2,andswitoh; 23, it is necessary; only, tomaintain the; initialcut-oiipotential on-the-grid 41 long enough. toq-keep; the switch w open duringthe succeeding surge. from-the secondary; winding 34 following theopening of the transformer primarycircui-t.

It for any reason it desiredto shut ofhthe flow of; coffee, brew beforethe; deranter, is filled to the: level at which the automatic. con-trolgoes into operation, this be doneby manually opening the pushbuttonswitch 28. This.:,switch is included in the; transformerprimary circuitand servesto interrupt the currentisupplytothe electronicrelayand-at-thesame time to the'windingslw and 21-.

The sectional view, Fig. 3, shows how the handlefitlis. clampedbetweenthe two endportions oi the collar 52,-; and: also illustrates aconvenient andsatisfactory mode of anchoringthe probe 54 whilevretaining the same i-nielectrical connection withthe collar. It will beseen that one endporion of thecollar is secured to the handle byneanszof. two=screws Bil; eachengagingia nut Gil having a screw-slottedhead bearing against the outer surface of the collar, while the otherend portion of the collar is d'etachably secured to the handle by meansof a thunibscrew 52. The anohored'endloi the probe is coiled-to form'aneyelet which encircles the upper nut 6i and is seated in a recess formedin the handle underneath the adjacent end portion of the collar 52 withwhich the eyelet: makes contact, being clamped-between the, handle: andthe contiguous inner surface of the collar. Since there isnormally acertain amountiof breakage of glass decanters consequent upon, use:thereof, it is important provision be made. for quick and easy removaland attachmentofi the collar- 52. This isreadily accomplishedzwith' theconstruction illustrated and described.

In the modification of Figlefil have dispensed with the wire probe 4 andsubstituted in its place a metal stripe 64 which is firmly adheredthroughout its length to the surface of the glass. This stripe extendsfrom the exterior of the decanter neck where contact is made with thecollar 52, over the top rim and downwardly inside the neck to a pointcoinciding with the level to which it is desired to fill the decanter. Ametal stripe at so disposed performs the same function as the wire probe54 of Fig. 2,

Instead of two separate tubes 36 and 31, I may prefer to use a singletwin triode, in which case the grid associated with the rectifier halfof the tube is connected directly to the adjacent cathode.

The auomatic liquid level control system of this invention is readilycapable of being so sturdily constructed that it is unlikely to requireservicing for long periods of time, save possibly for occasional vacuumtube renewals which can be performed without prolonged interruptions,provided a spare tube is kept at hand. Moreover, should a failure occurin any part of the system, it will result in shutting off the flow ofhot water,

there beingxpractitally no: possibility: of therwaten not being. shut edinsuch eventlunlessithevalve i-Zsfails'to closedueto somemechanicaledefect:

I claim:

1. An appzaaratus. including a receptacle, meansfor conducting. liquidinto the receptacle, anelectrio control 1 circuit having aterminal,inla' liquid stream flowing into the receptacle anda'second' terminalpositioned to be contacted: by the pool of liquid the receptacle, saidcircuit being adapted to: be completed between the terminals throughsaid liquid stream and the pool when the pool ofliquid within thereceptacle contacts said second terminal.

2. An apparatus including a reeeptacle, means for conducting liquidintothe receptacle, an automatic liquid control system for shutting'offthe flow of liquidto the receptaclewhen the liquidleveltherein reaches apredeterminedheight, said controlsystem including anelectricallycperated valve for controlling the liquid flow, and acontroicircuit for said valve havinga terminal in theliquid stream flowing intothereoeptacleand a secondterminal positioned to be contacted the poolof' liquid inthereceptacle, said circuit being adaptedto be completedbetween the tel-"m1 als through'said liquid stream and the poolwlien-the poolof liquidwithin the receptacle contacts said secondterminal;

An apparatus including a receptacle, elecally'eon'ductivemeansfordirecting a stream into the receptacle, an automaticliquid level control system for shutting oil'- the'fiow of liquid to thereceptacle when the liquid level therein reaches a predetermined height,said control system including an electrically operated valve forcontrolling the liquid flow, a relay for controlling said valve, and acontrol circuit for the ly having a terminal electrically connected; to:the liquid directing means and' a second terminalwithin the receptacleabove the bottom thereof, said circuit being adapted to be completed'between-the terminals through said liquid strearnand'the pool when thepool of'liquid withnrthe receptacle reaches the level ofthesecondterminal.

4. An apparatus including a'receptacle, means for delivering astream of"liquid flowing through space into the receptacle, an automatic liquidevel control system for shutting off'the flow of liquid to. thereceptacle when the liquid level therein reaches a predetermined height,said control system including an electrically-operated valve forcontrolling the liquid flow, and a control circuit for said valve havinga first terminal connected to the liquid stream flowing through spaceinto the receptacle and a second terminal in the receptacle positionedto be contacted by the pool of liquid in the receptacle when said liquidreaches a predetermined level whereby to complete the circuit betweenthe terminals through said liquid stream and the pool only when thelevel thereof reaches said predetermined level.

5. An apparatus including a receptacle, means for conducting a stream ofliquid into the receptacle, a completely electrical automatic liquidlevel control system for shutting off the flow of liquid to thereceptacle when the liquid level therein reaches a predetermined height,said control system including a normally-closed electrically-operatedvalve for controlling the liquid flow, an electronic relay operativewhen energized to open the valve and hold the same open during continuedenergization, said relay having a control grid normally at cathodepotential to permit the flow of current, and an electrical controlcircuit including said control grid and having a first terminalconnected to the liquid stream flowing into the receptacle and a secondterminal in the receptacle positioned to be contacted by the pool ofliquid in the receptacle when said liquid reaches a predetermined level,whereby to complete said circuit between the terminals through saidliquid stream and the pool when the pool of liquid within the receptaclereaches said predetermined level and impress a negative cutoff potentialon the grid to de-energize the electronic relay for closing said valve.

6. An apparatus including a receptacle, means for conducting a stream ofliquid into the receptacle, a completely electrical automatic liquidlevel control system for shutting oil? the flow of liquid to thereceptacle when the liquid level therein reaches a predetermined height,said control system including a normally-closed electrically operatedvalve for controlling the liquid flow, a primary circuit including asource of a1- ternating current and a normally open starting switch inseries with the actuating winding of the valve, an electrically operatednormally-open holding switch having its contacts in shunt with thecontacts of the starting switch, an electronic relay including a platecircuit, a control grid circuit having a grid normally at cathodepotential, and a rectifier circuit, a transformer coupling the relay tothe source of current through the starting switch, the actuating windingof the holding switch being included in the plate circuit, and a controlcircuit having a first terminal connected to the liquid stream flowinginto the receptacle and a second terminal in the receptacle positionedto be contacted by the pool of liquid in the receptacle when said liquidreaches a predetermined level whereby to complete the control circuitbetween the terminals through said liquid stream and the pool when thepool of liquid Within the receptacle reaches said predetermined leveland impress a negative cut-oil" potential on the grid to de-energize theelectronic relay for closing said valve.

7. A coffee-making apparatus including a decanter, means spaced from thedecanter for directing coffee brew into the decanter, an electricallyoperated valve for controlling the liquid flow, an electronic relay forcontrolling the operation of the valve, a first terminal mounted on thedecanter and extending into the same to a point coinciding with thelevel at which the decanter is to be filled with coffee brew, said relayhaving a control circuit including the terminal and having a secondterminal connected to the liquid stream flowing into the decanterwhereby to complete the control circuit between said terminals throughsaid liquid stream and the pool when the pool of liquid within thedecanter reaches the predetermined level and electrically contacts saidfirst terminal, and manually operable switch means for opening saidvalve to start the flow of coffee brew.

8. The method for completing an electrical control circuit to operate ashut-01f valve which comprises connecting one terminal of the circuit tothe liquid stream controlled by the valve, positioning the otherterminal of the circuit in a confined space and directing the streaminto said space to form a rising pool of liquid therein to complete thecircuit through the pool and stream when said pool contacts said otherterminal.

9. The method for terminating the flow of a stream of liquid into areceptacle when the liquid level therein reaches a predetermined heightwhich comprises positioning one terminal of a flow-controllingelectrical circuit in said receptacle at said predetermined height andconnecting the other terminal of said circuit to said stream whereby thecircuit between the terminals is completed through the stream and theliquid in the receptacle when the level thereof reaches said oneterminal.

HARVEY R. KARLEN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Re. 22,8779 Peters et al May 13, 1947 563,464 Fahrney July 7,1896 1,346,898 'Kingsbury July 20, 1920 1,869,720 Strand et a1. Aug. 2,1932 2,017,368 Magner Oct. 15, 1935 2,202,197 Ewertz May 28, 19402,323,128 Hare June 29, 1943 2,433,599 Cohen Dec. 30, 1947 2,483,450Wolfner Oct. 4, 1949 2,544,917 Dahlem Mar. 13, 1951

